Combination fuel pump and fuel injector for diesel engines



- May 31, 1932. H. LE PUL COMBINATION FUEL PUMP AND FUEL INJECTOR FOR DIESEL ENGINES Filed Oct. 6. 1950 Qvwentoz HENRY L PUL, 33111115 flame/641M q i Patented May 31, 1932.

HENRY LE PUL, OF HEMPSTEAD, NEW YORK COMBINATION FUEL PUMP AND FUEL INJECTOR FOR DIESEL ENGINES.

Application filed October, 6, 1930. Serial No. 486,532

This invention relates to new and useful improvements in a combination fuel pump and fuel injector for Diesel engines, and relates particularly to the subject matter of F my copending application, Serial No. 407,802

filed on November 18th, 1929.

In the copending application, it is proposed to provide a body member comprising a top section with a reduced cylindrical lower .0 end and acentral bore, an intermediate tubular section engaged on and extending below said reduced lower end, and an outer section encasing said intermediatesection and fixedly connected with the inner section and 5 formed with a closed bottom having an axial fuel discharge consisting of a small conical recess connecting with a coaxial passage, a plunger slidably mounted in the bore of said top body section and formed at the bottom 1 withan enlarged head slidably mounted in the portion of the intermediate body section below the top body section and normally slightly spaced from the lower end of the inner body section for forming an annular fuel compression chamber, a blow off valve in said plunger head interposed in a passage between said fuel compression and the side of a small conical projection engaging for closing the passage and the fuel discharge and projecting from the bottom of said plunger head.

The operation according to the above construction consists in the plunger moving upwards to compress the fuel within the fuel chamber, and the blow off valve being set so that the pressure reaches a very high one, such as 5000 pounds per square inch, before fuel discharges through the passage and strikes against the conical recess and continues through the fuel discharge passage. The upward motion of the plunger produces a new chamber beneath it sothat air from the cylinder of the Diesel engine, which is normally at a. p ssure of 500 pounds, may move through thefuel discharge passage and fill up the newly formed chamber. This chamoer is quite small so as to support but a small percentage of the combustion qualities of the fuel. The passage of air from the engine :ylinder into this newly formed chamber opposes to a very small degree the discharge of fuel through the passage into the cylinder of the engine.

It is an object of thisinvention to provide means for reducing the size of the newly formed chamber to a minimum so as to reduce the retarding effect of the incoming air upon the discharging of the fuel, and also to reduce the combustion of the fuel within the newly formed chamber.

It is particularly proposed to provide a projection with vertical sides from the bottom of the plunger head and terminating in said conical projection, and slidably engaging within, a portion of the bottom of said outer body section so as to limit the size of the passage chamber beneath the plunger head formed by the upward motion of the plunger to force fuel from the fuel compression chamber through the passages and the fuel discharge in said closed bottom.

For further comprehension of the invention, and of the objects and advantages thereof, reference will be had to the following description and accompanying drawings, and to the appended claim in which the various novel features of the invention are more particularly set forth.

In the accompanying drawings forming a material part of this disclosure Fig. 1 is a vertical sectional View of a combination pump and injector constructed according to this invention, certain parts being shown in elevation. I

Fig. 2 is a horizontal sectionalview taken on the line 2-2 of Fig. 1.

Fig. 3 is a horizontal sectional view taken on the line 3-3 of Fig. 1, and

Fig. 4 is anenlarged detailed view of a portion of Fig. 1 showing all parts in section.

The combination fuel pump and fuel 1nj ector for Diesel engines consists of a plunger 10 for operation by the cam shaft of an engine and working in a body member 11 formed with an inlet passage 12 connecting with a fuel compression chamber 13, said plunger 10 being arranged upon its injecting stroke'to pass said inlet passage 12 and entrap and compress the fuel within the chamber 13, and a blow ofi valve 14 connected with fuel chamber 13 for directing the discharge of clamped teeth 25, and with The said outer section end to a small distance fuel under pressure into a cylinder of the said engine. The body 11 is made from several sections and only one of said sections being length, and also has a bottom reduced portion 19, a central flange portion 20 and a top ex ternally threaded portion r 21. I

The said intermediate section 16 has a central bore 22 extendingits fulllength and is slidably mounted on the bottom reduced portion 19 of the inner section 15. The intermediate section 16'extends materially below A t1on 50 const1tut1ng a valve the bottom end of the inner section 15. packing gland 23 is threadedly engaged in the intermediate section and packing 24 is beneath the gland and between the inner and intermediate sections for providin a fuel tight connection. The interme-- diate section 16 is formed with lateralrack a transverse aperture constituting the said inlet passage 12. This aperture is positioned a small distance below the bottom end of the inner section 15.

'17 is provided with a central bore 26 extending through its ton from the bottom end, and is adapted for attachment upon the cylinder of an engine. The outer section terminates atthe top in a pair of lugs 27 which are engaged against the bottom side of the said central flange 20. Screws 28 engage through the flange and into the lugs for holding the outer section in fixed relation to the inner section. outer section 17 aligns with the passage 12 in the central section. A pair of lugs 30 project from one side of the outer section 17 an support with teeth at one end meshing with the rack teeth '25. A control lever 33 is attached upon the pin 31 so that upon motion of the lever, the rocker arm moves for raising or lowering the intermediate body section 16. A valve seat 34 is formed in the outer bodysection 17 at the bottom of the bore 26 and connects with a passage 35 for discharging into a cylinder of the engine. p v

'The said plunger 10 has a finished central portion 36 and an enlarged bottom head37. The central portion 36 isslidably engaged through thebore of the inner section 15 and is formed with a plurality of packing grooves 38 adapted to be filled with oil for forming an oil packing. A packing gland 39 threadedly engages in the inner section and forces packing material 40 tightly between the inner '52. An expansion spring A lateral passage 29 in "the 1 valve 50 is open to the passage 35. n a pin 31 carrying a rocker arm 32 outer body section .17,

section and the central portion of the plunger rod for forming a liquld tight joint. The enlarged head portion 37 of the plunger is disposed within the intermediate body bore. The top of the enlarged head portion 37 is slightly spaced from the bottom end of the inner body section 15 providing a space which constitutes the. fuel chamber 13. A transverse fuel aperture fuel chamber 13. A longitudinal fuel passage 46 connects with the transverse passage and communicates with .a. bottom bore 47 formed in the bottom end of the plunger 10. 30

plunger and is formed with a bottom pr0jec-. 85

head for acting against the said valve seat 34 in the outer body section 17. Fuel passage grooves 51 extend from the valve head: to a bore 52 within the bottom plug 49 and the bore 47 in the plunger. is slidably engaged within the bores 47 and 54 normally urges the valve head against the seat 48.

A filler rod 55 is attached upon the valve 9 head and passes through the central opening 1 of the spring 54 so as to fill up all excess the compass of fuel colspaces for reducing lecting-in the bore 47 and 52. The valve head 53 is slightly shorter than the overall 100 length of the bores 47 and 52 so as to provide a slight space 56 permitting a slight longitudinal movement of the valve. As shown in Fig. 4 the valve is of hollow construction so as to house the expansion spring 54. A fuelpassage groove '57 is formed upon the, periphery of the valve 53 so as to permit the passage of fuel from thelongitudinal passage 46 to the passages 51 and hence if the The bottomprojection 50 has vertical sides and a conical free end., The vertical sides in the bottom of the and the conical end engages within a bore engages said valve seat the upper portion of the conicalprojection 50 is greater than the diameter of the valve bore 47 so that the'fuel passages 51 may not break out from the sides of the projection and terminate in the conical portion a slight distance from the apex so that when the plunger head is in its lowered position, the projection 50 acts as a valve and closes the passage'through the passage 35 and thepassages 51. The should be very small, in fact'as small as it is possible to make it, relative to the diameter of the plug 49. The height of the vertical s1des of the projection 50 should be greater than the stroke of the plunger, that is, 1

which aligns with 9 A valve head 53 34. The diameter of 1 diameter of the projection 50 1 section 16 and is a slidable fit in its central 45 is formed within y the plunger 10 and communicates with the spiral greater than the height of the compression chamber 13 so that when the plunger." is: in its highest position, the vertical sides of the: projection 50 will not disengage from the bore in the body sectioii 17.

A spring housing 58 is threadedly engaged upon the threaded portion 21 of the. innerbody section. A collar-59 is fixed upon. theplunger and between the collar and the spring housing 58 for normally urging the plunger downwards. Lugs 61 project from the spring housing 58 and support a pin 62 carrying a,

rocker arm 63 engaging the bottom side off intermediate body section the collar 59. lever 64 is fixed upon the pin 62 and is intended for connection with the cam shaft of the engine.

In operation of the device, a supply of fuel is fed into the passage 29. This fuel enters the fuel chamber 13 through thepassage 12. At the proper moment, the cam shaft of the engine, the lever 64 is moved so that the rocker arm- 53 lifts'the plunger 10. As the plunger moves upwards, the head portion 37 forces back all excess fuel from the fuel chamber 13 until it passes the passage 12 and then compresses the entrapped fuel within the chamber-l3. Continued upward motion of the plunger soon raises the pressure of the entrapped fuel to a predetermined amount as determined by the strength of the spring 54. I

As this pressure is reached, the valve 53- automatically moves downwards and the fuel is then free to enter the passage 46, continue along the spiral groove 57, continue along the passages '51 and finally discharge from the passage into the cylinder ofthe engine. Obviously, this fuel is discharged at a high pressure which is necessary since the pressure within the cylinder of a Diesel engine during intake is about 500 pounds. It is very easy to raise a pressure of the inlet fuel to 5000 pounds or more with this arrangement.

As the plunger 10 moves upwards, a small :hamber is formed beneath the conical proection and the body section 17. The proection 50 moves upwards, but at all times maintains contact with the body section 17 o as to divide off this chamber from another hamber section which is formed to the botom of the plug 49 and the body section 17.

As the plunger 10 moves upwards so as o compress the fuel within the fuel chamber 3 to a high pressure so that the'valve 14 pens to discharge the fuel under pressure irough the passage 35, air from the cyliner will tend to enter into the newly formed iamber, but since this chamber is so very nall this air will be of a negligible quantity.-

he air will not hinder the discharge of the 1cl through the passages 51, then against [(-3 inclined sides 34 and through the pasge 35, in that the fuel is under a very much 'eater pressure than the air which tends to an expansion spring acts as determined by as to limit travelfinwards. The small formed chamber which may enter newly beneath projection 50 is so small that. it can support but a very small; percentage. of thecombustibl'e qualities of the discharged. fuel, so that the greater percentage of the; will'burn within the cylinder of the; Diesel. engine.

The quantity of fuel injected into: the engine at each operation of the device be controlled by manipulation of the; lever 33.. Motion of; the. lever moves the rockerarm 32 and consequently raises or lowers the; 16. As the: body section is raised,. the. position of the fuel passage 12 is changed relative to' the bottom and of the inner body section 15. Coliseqllliently the size of the portion of the, fuel camber which. holds the entrapped fuel; is varied.

While I have illustrated and described my invention with' I- realize that in practice various alterations therein maybe made. I therefore reservethe right and privilege of changing the form. of the details of construction or otherwise altering the arrangement of the correlated parts without departing from the spirit or" the scope of the appended claim.

Having thus described my invention, what I claim as new, and desire to-secure by United States Letters Patent is In a combination fuel pump and fuel injector for Diesel engines, a body member comprising a top section with a reduced cylindrical lower end and a central bore, an intermediate tubular section engaged on and extending below said reduced lower end, and an outer section encasing said intermediate section and fixedly connected withthe top section and formed with a closed bottom having'an axial fuel discharge consisting of a small cylindrical recess with a conical pointed end connecting with a coaxial passage, a plunger slidably mounted in the bore of said top body section and formed at the bottom with an enlarged head slidably mounted in the portion of the intermediate body section below the top body section and normally slightly spaced from the lower end of the top body section for forming an annularv fuel compression chamber, a small cylindrical element with a conical point projecting from the bottom of said plunger head and engaging in said cylindrical recess for closing the, fuel discharge and of sufficient length so as not'to disengage from the recess upon complete upward motion of said plunger, ablow off valve interposed in a passage between said fuel compression chamber and the side of said conical point, andsaid cylindrical element slidably engaging the cylindrical recess in the bottom of said outer body section so the size of the chamber beneath the plunger head formed by upward motion some degree of particularity,

of the plu'nger for forcing fuelfrom the fuel compression chamber through the passages and the fuel discharge in said closed bottom. Signed at New York, in the county of New 5 York and State of New York, this 26th day of September, ALD. 1930. I

HENRY LE PUL. 

